A construction industry has recently kept pace with construction of futuristic buildings, which have become larger and multifunctional. Also, due to limited site conditions, buildings have a tendency to be constructed with high floors and with underground floors. Therefore, a steel construction process for constructing basic steel structures has been recognized as the most important construction process among construction processes for a large-sized building in accordance with the tendency of a recent construction industry. The steel construction process is an essential process of the construction processes for large-sized buildings and is a process for constructing frames of the buildings. The basic work of such a steel construction is to pull up various steel structures by using a tower crane installed at a construction site and to assemble the steel structures up to a desired floor by workers.
In order to set up such a steel structure, first, a steel structure has to be connected to a tower crane, etc. by using a shackle assembly, etc. That is, as shown in FIG. 1, connection members 120 having each assembling hole 121 are welded to both sides of an upper end of a steel structure 110, respectively. A shackle body 131 included in a shackle assembly 130 is fixedly assembled with the connection members 120 through an assembling hole 121 by using a shackle pin 132 and a nut 133, and then, a hook 140 of the tower crane is connected with the shackle body 131.
Then, after the steel structure 110 connected with the hook 140 of the crane is pulled up, the steel structure 110 is accurately moved to an assembling position to be temporarily assembled. Then, the worker climbs to an upper part of the steel structure 110 and separates the shackle assembly 130 from the steel structure 110.